Essential oils: from extraction to encapsulation.

Essential oils are complex blends of a variety of volatile molecules such as terpenoids, phenol-derived aromatic components, and aliphatic components having a strong interest in pharmaceutical, sanitary, cosmetic, agricultural, and food industries. Since the middle ages, essential oils have been widely used for bactericidal, virucidal, fungicidal, antiparasitical, insecticidal, and other medicinal properties such as analgesic, sedative, anti-inflammatory, spasmolytic, and locally anaesthetic remedies. In this review their nanoencapsulation in drug delivery systems has been proposed for their capability of decreasing volatility, improving the stability, water solubility, and efficacy of essential oil-based formulations, by maintenance of therapeutic efficacy. Two categories of nanocarriers can be proposed: polymeric nanoparticulate formulations, extensively studied with significant improvement of the essential oil antimicrobial activity, and lipid carriers, including liposomes, solid lipid nanoparticles, nanostructured lipid particles, and nano- and microemulsions. Furthermore, molecular complexes such as cyclodextrin inclusion complexes also represent a valid strategy to increase water solubility and stability and bioavailability and decrease volatility of essential oils.

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Essential Oils Loaded in Nanosystems: A Developing Strategy for a Successful Therapeutic Approach

The food industry expects increasingly complex properties (such as delayed release, stability, thermal protection, and suitable sensorial profile) from food ingredients, which often would not be able to be achieved without microencapsulation. This paper presents the state of the art in encapsulation technology for delivery of bioactive compounds to food. It reviews common encapsulation technologies (emphasizing their advantages and limitations) versus novel, interesting approaches in emerging technologies. This review includes a presentation of benefits resulting from the use of microencapsulated ingredients in the food industry; these benefits are going to be illustrated via few case studies bringing innovative processing. Spray drying has been used for more than 60 years to protect flavor oils against degradation/oxidation/evaporation, but melt dispersion technique has been used lately to effectively stabilize an aroma compound. Microgels produced by extrusion and emulsification techniques are considered for delivering synergistic antioxidant effects of plant extract polyphenols, their off-taste masking, and improved handling. Apart from microgels, microemulsions (produced by microfluidization or micelle formation techniques) are taken into account for entrapment of extracts containing polyphenols and essential oils. Innovative and interesting coacervation processes are depicted here as they facilitate the commercialization of coacervated food ingredients. Liposomes are gaining increasing attention in the food sector as they can provide good stability even in a water surrounding and also targeted delivery. The new scalable manufacturing protocols for the production of liposomes evolved in recent years (e.g., proliposome method) are presented here. Fluidized bed technology has been offering a versatile possibility to produce encapsulates which should release ingredients at the right place and the right time. Complex systems such as lipids in hydrogels are newly developed structures for controlled release of bioactive compounds. Finally, the effect encapsulates have when incorporated into real food products will be discussed, in particular with regard to the production of innovative functional food products. As an example, textural, sensorial, and physical quality assessment of chocolates enriched with encapsulated polyphenolic antioxidants from yarrow (Achillea millefolium L.) will be reviewed.

Trends in Encapsulation Technologies for Delivery of Food Bioactive Compounds

Polysaccharide-based nanoparticles by chitosan and gum arabic polyelectrolyte complexation as carriers for curcumin

Agrochemicals are used to improve the production of crops. Conventional formulations of agrochemicals can contaminate the environment, in particular in the case of intensive cropping. Hence, there is a need for controlled-release formulations of agrochemicals such as polysaccharides to reduce pollution and health hazards. Natural polysaccharides are hydrophilic, biodegradable polymers. This article reviews the use of polysaccharides in the form of micro- and nanoparticles, beads and hydrogels. The main points are: (1) slow release formulations minimize environmental impact by reducing agrochemical leaching, volatilization and degradation. For example, 50 % of the encapsulated insecticide chlorpyrifos is released in 5 days, whereas free chlorpyrifos is released in 1 day. (2) Slow release formulations increase the water-holding capacity of soil. (3) Slow release formulations better control weeds in the long run. (4) Polymer-clay formulations store ionic plant nutrients. (5) Polymer hydrogel formulations reduce compaction, erosion, and water run-off. They increase soil permeability and aeration, infiltration rates, and microbial activity, and, in turn, plant performance. In conclusion, polysaccharide formulations can be used for safer use of agrochemicals.

https://link.springer.com/content/pdf/10.1007%2Fs13593-014-0263-0.pdf

Fan Yang

Papers

Formation of heat-resistant nanocapsules of jasmine essential oil via gelatin/gum arabic based complex coacervation